i'd like to build a report with several columns (market sales current year, market growth to previous year etc.) with one row per Category. One of the columns should show the Rank of my Company within this Category. E.g. in Product Category 1 I'm on position 2, in Category 2 I'm on position 4. Is there any smart way to do this in one report?

Refer the below snapshot. If this is you are looking at then you just need to create a calculated field Rank = Rank(SUM([Sales])). But, result given by you is not the same. But as per view, its correct. Workbook is also attached.

Sorry may be i am struggling to get your requirement. You want My Corporation rank in each category and don't want to show corporation in the View. If this is correct, refer the below snapshot and attached workbook.